Measurement of Broadband Dielectric Constant Using Substrate Integrated Waveguide

In this paper, a novel method to measure broadband dielectric constant using substrate integrated waveguide (SIW) is presented. Based on the transmission/reflection (T/R) method and multiline calibration procedures, two SIWs with different lengths are used to measure the dielectric constant of the substrate slab. The effective measurement frequency range covers the passband of the fundamental mode, TE₁₀ mode, of the SIW. To verify the developed method, the SIWs are fabricated on Rogers RO4003 substrate and measured in Ka-band, 26-40GHz. The measured results are shown in good agreement with those using the ring resonator method. It demonstrates that the proposed method is an effective approach to characterizing the substrate slab in millimeter-wave range